ncp5203 ON Semiconductor, ncp5203 Datasheet - Page 8

• Manufacturer Part Number: ncp5203
• Description: 2-in-1 Ddr Power Controller
• Manufacturer: ON Semiconductor

VTT Active Terminator in Normal Mode (S0)
regulator with two internal N−channel power FETs to
provide transient current sink and source capability up to
2.0 A. It is activated in normal mode in S0 when the
VTTEN pin is high and VDDQ is in regulation. When in the
S0 state and VTT is in regulation, signal INREGVTT will
go high to notify the control logic block. The VTT regulator
is powered from VDDQ with the internal FET’s gate drive
power derived from 5VDUAL. The VTT output voltage
can be adjusted by using an external resistor divider
connected to the REFSNS pin. This regulator is stable with
any value of output capacitor greater than 470 mF, and is
insensitive to ESR ranging from 2.0 mW to 400 mW.
VTT Active Terminator in Normal Mode (S3)
VTT Active Terminator Fault Protection
bi−directional current limit is implemented, preset at 2.4 A
magnitude. This current limit is also used as constant
current source during VTT startup.
The VTT active terminator is a two−quadrant linear
VTT output is high−impedance in S3 mode.
To
provide
protection
for
the
internal
http://onsemi.com
FETs,
NCP5203
8
VTT Active Terminator Thermal Consideration
output currents. If large currents are required for very long
duration, then care should be taken to ensure the maximum
junction temperature is not exceed. The 5x6 QFN−18 has
a thermal resistance of 35_C/W (dependent on air flow,
grade of copper, and number of vias). In order to take full
advantage of this thermal capability, the thermal pad
underneath must be soldered directly to a PCB metal
substrate.
Supply Voltages Undervoltage Monitor
5VDUAL pin. 5VDLGD is set high if 5VDUAL is higher
than its preset threshold (derived from VREF with
hysteresis). The IC will later latch off if 5VDUAL is in S0
providing both VDDQEN and VTTEN remain high.
Thermal Shutdown
entire IC will shutdown. The IC resumes normal operation
only after 5VDUAL or VDDQEN is cycled.
The VTT terminator is designed to handle large transient
The IC continuously monitors 5VDUAL through the
If the chip junction temperature exceeds 150_C, the